Engine provided with lubricating structure

Abstract

A single cylinder engine includes a crankcase having a crank chamber, a crankshaft disposed in the crank chamber of the crank case and having a crank web with a side surface perpendicular to a rotating shaft of an engine, and a lubricating structure for lubricating oil to components in the engine. The lubricating structure includes an oil reservoir communicating with the crank chamber through an oil discharge port formed to the crank chamber under the crank chamber, and an oil discharge groove formed to the crankcase for discharging oil flying from the crank web into the oil reservoir, the oil discharge groove being provided in a side wall of the crankcase facing a side surface of the crank web in the crank chamber.

What is claimed is: 
     
       1. An engine provided with a lubricating structure, comprising:
 a crankcase having a crank chamber; 
 a crankshaft disposed in the crank chamber of the crank case and having a crank web with a side surface thereof perpendicular to the crankshaft; and 
 a lubricating structure for lubricating an oil to components in the engine, the lubricating structure including an oil reservoir communicating with the crank chamber through an oil discharge port formed to a bottom portion of the crank chamber, and an oil discharge groove formed to a side surface of the crankcase continuous to the bottom portion of the crank chamber and configured to discharge oil flying from the crank web into the oil reservoir, the oil discharge groove being provided in a side wall of the crankcase facing the side surface of the crank web in the crank chamber and configured such that the oil discharge groove is provided to be shallow in the vehicle width direction in an upper part of the oil discharge groove thereof and to gradually deepen towards a lower part of the oil discharge groove thereof. 
 
     
     
       2. The engine provided with the lubricating structure of  claim 1 , wherein the engine is a single cylinder engine. 
     
     
       3. The engine provided with the lubricating structure of  claim 2 , wherein the crank web has a disk shape and the oil discharge groove has a circular arc shape around the crankshaft in a region corresponding to an outer peripheral portion of the crank web. 
     
     
       4. The engine provided with the lubricating structure of  claim 2 , wherein the oil discharge groove is provided up to an end portion of the side wall of the crankcase. 
     
     
       5. The engine provided with the lubricating structure of  claim 2 , wherein the oil discharge groove is provided to be deeper in a vehicle width direction toward the oil reservoir. 
     
     
       6. The engine provided with the lubricating structure of  claim 2 , wherein the oil discharge groove is provided below the crankshaft. 
     
     
       7. The engine provided with the lubricating structure of  claim 2 , wherein the oil discharge groove is provided on an upstream side of the oil discharge port in a rotational direction of the crankshaft.